Ultracapacitors, Batteries Join Forces for Fuel Efficiency

Ultracapacitors also enable automotive manufacturers to answer safety and performance critiques by reliably completing a million or more charge-discharge cycles in all weather conditions, without having to be replaced. Hybridized energy storage and power delivery solutions with both ultracapacitors and batteries enhance the performance of hybrid and electric vehicles by meeting the electrical power demands of acceleration, power steering, electrical systems, and starter systems, and they play a significant role in start-stop and regenerative braking systems solutions.

Ultracapacitors can absorb and store essentially all the kinetic energy from a braking system. Their efficiency and power capability add up to more efficient recapture of braking energy. This energy is then available to help in acceleration to decrease fuel consumption and associated emissions.

In full hybrid or electric vehicles, ultracapacitors can lessen battery drain and prolong battery life. This regenerative braking solution takes most of the load off mechanical brakes, reducing brake maintenance and replacement expenses. Ultracapacitors can also complement batteries in start-stop applications, which enable the engine in a conventional, electric, or hybrid-electric vehicle to shut down when it comes to a stop at a red light or when sitting in traffic. Ultracapacitors then provide a short burst of energy that restarts the motor.

Are their app notes or designer guidelines to help us size the ultra capacitor for the cell size and capacity?

For example, single cell NiMH, LiON chemistries, and lead-acid batteries are going to have practical charge and discharge limits, typically a multiplier of the cell C rating. Given the C limit, what sort of capacitance provides what sort of C range extensions?

I know this reads like a Gadge Freak proposal but having a guide lets the designer make a practical choices.

The capacitor(s) are smaller and lighter than most would think. I agree with what Jermey is trying to say in his article. My company www.koldban.com has been marketing our KAPower supercapacitors for engine starting for several years. The key here is that no one current technology offers both power and energy. Power being how much and energy being how long. By using a supercapacitor (a.k.a. ultracapacitor) in combination with a battery, it will minimize a battery's exposure to any high power transients. Thus, allowing the battery to do what it is good at and that is providing energy. In addition, in applications with multiple batteries one or more of the batteries can be removed since they are no longer needed to supply power. ie: engine starting.

Jim, I tend to agree with your statements, but there is so much more that is not disclosed by the author. This is more of a puff piece than what I would expect in something published by engineers for engineers. What is the basic technology? What are the tradeoffs? I remember the earliest ultracaps (just a few years ago) were very low voltage (a few volts WVDC at best) and had an absurdly high internal resistance. What allows these units to be described as essentially lossless? Without some hard information and checkable references, this could easily be pie in the sky!

The article doesn't address the size of cap needed for this. Let's say we have 1000F. The delta V ov the cap is say 100V on top of the normal 380V rail. This contains enough energy to power a 50Kw motor for 100 sec. assuming everything 100% efficient. While this would fill gaps for accelleration/decelleration, How big and heavy is a 1000F cap rated at say 600V?

It will be interesting to see how they manage surge currents. Unlike a battery where the voltage drops considerably when a near dead short occurs as a starter engages, ultra capacitors will instantly pump near infinite current. They'll need to have a very robust wiring and electrical contact switching system to handle this.

Anytime you have to start up a motor repeatedly a big cap is the way to go. Most of the time the expense of the capacitor precludes you from including it in the design, but an electric car is the perfect application. The Bill of Material cost just isn't as important as performance is. At least, for now.

I have gotten to use super capacitors in an application where battery life was very important.

Good article which presents many good points. In addition to the previous question on why we haven't seen these earlier (cost/economic reasons?) it would also be interesting to know the weight per capacity tradeoff (i.e. larger capacitors can carry a larger charge, but are also heavier and can slow vehicle performance). How is the size of the capacitor optimized for each vehicle?

I can follow the wonderful things ultracapacitors can do according to the article. The items listed sound logical and seem to be exiating technology. So why haven't we seen or heard about automakers doing these things? Are they married to battery makers? As far as gasoline prices going down when consumption does I don't think that will ever happen. If it does it will be in far, far distant future.

Industrial workplaces are governed by OSHA rules, but this isn’t to say that rules are always followed. While injuries happen on production floors for a variety of reasons, of the top 10 OSHA rules that are most often ignored in industrial settings, two directly involve machine design: lockout/tagout procedures (LO/TO) and machine guarding.

Load dump occurs when a discharged battery is disconnected while the alternator is generating current and other loads remain on the alternator circuit. If left alone, the electrical spikes and transients will be transmitted along the power line, leading to malfunctions in individual electronics/sensors or permanent damage to the vehicle’s electronic system. Bottom line: An uncontrolled load dump threatens the overall safety and reliability of the vehicle.

While many larger companies are still reluctant to rely on wireless networks to transmit important information in industrial settings, there is an increasing acceptance rate of the newer, more robust wireless options that are now available.

To those who have not stepped into additive manufacturing, get involved as soon as possible. This is for the benefit of your company. When the new innovations come out, you want to be ready to take advantage of them immediately, and that takes knowledge.

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